Use cycles's denoiser on multi-layer EXRs
Take a look on B°WIDE nodepack:

https://bwide.wordpress.com/node-groups/bwide-nodepack-for-blender/

It has a PassCombineDeNoiser, that combines Cycles render passes &amp; denoise it pass by pass based on Normals. You can also denoize exr-files, if you have all needed layers. It looks similar to new denoizer